Sarcoidosis is a systemic granulomatous disease of unknown etiology that likely involves exposure to some environmental agent in a genetically susceptible host. We propose to identify sarcoidosis susceptibility genes and determine how these genes and environmental risk factors interact to cause sarcoidosis. This will be accomplished by organizing a multicenter consortium to recruit an adequate sample of sarcoidosis families for analysis. We plan to use affecting sibling pair linkage analysis to scan the genome for linked chromosomal regions, transmission disequilibrium testing to evaluate candidate genes in those regions with evidence for linkage and an environmental questionnaire to collect data to test for possible interactions of susceptibility genes with exogenous risk factors. This application offers the Department of Biostatistics and Research Epidemiology, Henry Ford Health System as the Data Coordinating Center (DCC) for the project. The DCC will provide administrative coordination, develop study documents, develop recruitment strategies, provide study tracking, establish a central data base, conduct data quality assurance, and collaborate with other members of the consortium in analysis of the results of the study. The Data Coordinating Center (DCC) will be an independent unit within the consortium, and will take guidance from the Steering Committee. The DCC team is headed by Principal Investigator Sarah Fowler, PhD, a senior biostatistical who specializes in coordinating centers for multi-center studies, and coordinating center biostatistician and Co-PI Mei Lu, PhD, who will sere as project manger for the DCC. DCC Co-Investigator Marvella Ford, PhD, will advise the collaborative group on the recruitment and retention of African American subjects and their families. The Coordinating Center team also includes a support staff consisting of individuals (programmer, data coordinator and secretary) experienced in and dedicated to methodologies for multi-center studies.